Though I have noticed that the people who choose no seem to be a lot more open about it, providing very good evidence, while the people who choose yes are staying quite, there hasn't really been an argument here. Why is that?

^ I just explained that, he was Sasori's agent from the start, that's how the timeline works.

His "adoption" was planned as part of his infiltration of Konoha.

That wasn't directly stated. They never directly connect Kabuto's stay at Konoha with his work as Sasori's agent. And we don't know the order of events realting to Konoha with relation to his work under Sasori either.
Though the idea that Kabuto was Sasori's agent from the start sounds good and would explain his wierd behavior in Konoha, there are too many unknowns to say that he was Sasori's agent from the start. We just know that he was Sasori's agent before Orochimaru's.

^ It was a "gift" since Orochimaru liked to collect people, but he was actually supposed to act as a sleeper agent.

Originally Posted by Urameshi-sama

That wasn't directly stated. They never directly connect Kabuto's stay at Konoha with his work as Sasori's agent. And we don't know the order of events realting to Konoha with relation to his work under Sasori either.
Though the idea that Kabuto was Sasori's agent from the start sounds good and would explain his wierd behavior in Konoha, there are too many unknowns to say that he was Sasori's agent from the start. We just know that he was Sasori's agent before Orochimaru's.

You're right.

But it was stated that he was Sasori's agent before he ever met Orochimaru.

It was also stated that he was "adopted" as part of infiltration of Konoha, ordered by Orochimaru.

Add the two together and it's easy to tell what order the events follow.

ultimately, i dont think that kabuto is loyal to oro, like others have said i also believe that he had another motive for working with him.

"Our deepest fear is not that we are inadequate.
Our deepest fear is that we are powerful beyond measure.
It is our light, not our darkness that most frightens us.
We ask ourselves, Who am I to be brilliant,
gorgeous, talented, fabulous?"
Actually, who are you not to be?

I think Kabuto is loyal to Orochimaru as long as it fulfills his purpose. Meaning that he has an ulterior motive and will go to any lenghtt (as we have seen) to help Orochimaru as long as it serves his own interests. Also, he has done all those experiments for Orichimaru but he has also saved Hinata and helped others in Konoha.

I would not be surprised to find out that Kabuto works for Danzou - lol

I think that his goal was just to keep Orochimaru alive (for his own purposed), not necessarily to serve Orochimaru's goals.

He would never have considered killing Sasuke if that were the case, and we know that he isn't compelled because Orochimaru stated that he never knew what was going on behind Kabuto's head and Kabuto said that Orochimaru did not use that sort of jutsu on him.